Container for nutrient media



Sept. 27, 1960 E. KANZ CONTAINER FOR NUTRIENT MEDIA Filed July 31, 1956 INVENTUR [M410 K/I/VZ $1 Lad/M4 1 drry The present invention relates to a novel container'for storing nutrient media for the'cultivation of microorganisms, as well as to the .processof using said container with nutrient media for testing purposes.

In order to isolate the individual species from a mixture of bacteria, i.e., to obtain pure cultures, and to investigate the species to determine their respective patho- I genie effects, there have heretofore been employed a mixture of broth and nutrient additives. A gelatinizing substance, such as gelatine or agar agar was'added to the fortified broth. The fluid mixture of nutrient liquid and agar agar was 'placed-into-a sterile Petri dish and permitted to coagulate by cooling so as to provide'a' sol-id nutritive substratum or medium. The material to"'be investigated, such as pus, feces, urine sediment, etc, was inoculated in a very small amount on this solid nutritive substratum so that the individualmicroorganisms contained in the material to be investigated were deposited separately on the nutritive substratum and adhered thereto.

The dish containing the inoculated culture medium is placed into a incubator at a temperature of about 37 C. and the isolated individual microorganisms multiply forming colonies clustered in the same locations as the original parent microorganisms. In about 24 hours the colony produced by a single microorganism will attain the size of a pinhead which is sufficient for microscopic examination.

Since the culture medium must in all instances be uncontaminated initially, it must be freshly prepared in advance of each investigation. The Petri dishes must also be sterilized before use and because of their cost they must be re-used. Consequently, residual microorganisms from previous experiments must be destroyed in the interest of safety and the dish must be re-sterilized by prolonged heating in air before each use. It is obvious that special sterilizing equipment was necessary in order to prevent the virile microorganisms from escaping into the atmosphere. The cost of this test procedure was therefore considerable due equally to the special equipment and the time-consuming sterilizing techniques which required skilled personnel.

Another test technique based on cultivation of microorganisms involves the preparation of test plates each containing a nutrient covered with filter paper impregnated with a different antibiotic. Pus from an infected patient is dropped onto each of the plates and they are all incubated, so as to propagate the infectious microorganism. Where the microorganism propagates a dense film covering the plate will be formed. Certain of the plates may be found to have a sterile halo which indicates that the propagation of the microorganism was inhibited by the particular antibiotic with which the paper was impregnated. It is therefore apparent to the physician that administration of that particular antibiotic to the patient will serve to combat the infection. The size of the halo will be quantitative indication of the eifectiveness of the antibiotics in the event that several are inhibitory.

2,954,327 Patented Sept. 27, 1960 The plates must be prepared with the same care as Petri dishes and the sterilization and cleaning are equally time-consuming. Even if the agar agar is supplied in sterile test tubes, the plates must be prepared by first melting the agar agar, pouring the liquid ontothe plates, allowing itto congeal and then sterlizing. The dishes and plates must be boiled in special steam vessels, treated with lye, then with acid and finally with pure water and again sterilized. before re-use is possible.

v Consequently, only laboratories with large staffs and expensive equipment are capable of running thetests indicated, and even so the cost per test is necessarily high. It is accordingly an object of the present invention to provide nutrient media in sterile condition in an inexpensive container which can be disposed of.

.It is a further object of the invention to providea novel process for making sterile nutrient medium-containing disposable containers.

These and other objects and advantages are realized inaccordance with the present invention wherein nutrient medium asagaragar, cooked blood agar, milk sugarindicator various selective nutrient medium etc., is put into a sterilized container made of synthetic material, such as resinous sheet material, so that the bag can b-e'stored without altering the sterile character of the contents. The container can be closed byheat sealing or by other means and when needed can be openedeasily and used directly. After the test has been made, the bag can be subjected to ashort treatment to destroy the infectiousmicroorganisms such as by being placed in a disinfecting solution which can be poured out. The decontaminated bag and contents can then be disposed of by flushing away or burning or in any conventional manner.

The novel bag containing sterile nutrient medium is especially suited for small laboratories, dairies, clinics, doctors offices, and the like. Because of the little space required, it is especially suited for flying laboratories and other mobile laboratories so that on the spot analyses may be made.

The bags are not subject to the breakage attending the use of glass or porcelain plates and they also afford suitable shipping containers for the sterile nutrient medium. Because of the pliability of the bag, when opened the nutrient medium may be directly pressed or dabbed against surfaces such as doors, walls, furniture, and the like, which are suspected of contamination, which is not possible with nutrient media contained in rigid dishes.

The invention will now be described with reference to the accompanying drawing which is a perspective view of a preferred embodiment.

The container comprises two sterilizable, chemically inert foils 1 and 2 of synthetic material such as polyvinyl chloride. After sterilization in superheated steam, the bag is filled with gelatinizable nutrient medium 3 and hermetically closed along its periphery such as by heat sealing so that a moisture-proof and bacteria-proof seal is established. Upon cooling the nutrient medium gelatinizes and can be exposed by either tearing off a corner or opening of the heat seal.

Alternatively, a tube of suitable synthetic material can be cut into predetermined lengths and sealed at one end to form a compartment for receiving the nutrient medium and can then be closed at the remaining open end. In this instance the foils 1 and 2 will be integral.

For the diagnosis of pathogenic intestinal bacteria, a foil 4, permeable to nutrient medium, can be arranged between the medium 3 and the cover foil 1, thereby subdividing the container into two compartments, one of which contains the nutrient medium. Upon opening the other compartment the foil 4 Will receive different bacteria and colonies are permitted to form upon incubation due to passage of the nutrient medium through the foil 4. The foil 4 can be locked in position during the heat sealing of foils 1 and 2 or it may be separately adhered along its periphery to the underside of foil 1 in such manner that by separating foil 1 subsequently the foil 4 is exposed.

After applying the specimens to be treated, either with or without the foil 4 present, the foil 2 and medium 3 are incubated in the conventional manner for propagation of the microorganism. The hitherto required covers of the Petri dishes may be replaced by arched covers which are simply put into the flame for a short time after and before each use. After the incubation, the results of the tests, such as the antibiotic test, may be read on the bag exactly as on the agar plate, only with the difference that in Petri dishes the exacting cycle for sterilization and the like has to follow whereas the bag simply may be thrown into a disinfecting solution and, after some hours, may be treated like any other waste, for instance, flushed away without any hesitation.

A bag according to the invention is especially suited for the diagnosis of heterogenic intestinal bacteria; in this case after the removal of the uppermost covering foil 1, the foil 4 of viscose or the like is present on the agar on which by means of an indicator spray a sharper difierentiation of the heterogenic intestinal bacteria may be effected than was heretofore possible by means of a nutritive substratum.

With the novel bag all the possibilities of the Fliife process according to the German Patent 839,254 may be realized, such as dynamic nutritive substrata, indicator, aerosol, the use of isotopes for the serological detection, etc. Entirely new possibilities of breeding and diagnosing exist also for the microbiological symbiose research.

This permits a faster growing of the cultures, the possibility of sending of air dried investigating material on foils, the preparation of Fliife and anaerobic cultures, microscopic control during propagation, the production of mass cultures for obtaining vaccines and large quantities of bacteria free from agar, and the preparation of toxins.

Difierent nutrient media may be placed in different bags and all stored together, difierentiat-ion being possible through markings. Even a small laboratory can thus have a variety of media and can select the particular medium necessary for each investigation.

Various changes and modifications can be made without departing from the spiritand scope of the present invention and it is intended that they be embraced by the annexed claims since the foregoing description is illustrative of the, invention rather than limitative thereof.

I claim:

1. The process whichcomprises forming a container of sterilizable synthetic plastic material, subdividing said container into two compartments by means of a permeable foil, sterilizing said container, pouring into one of said compartments a sterile nutrient medium for the propagation of microorganisms and hermetically sealing said container, whereby upon opening the other of said compartments and applying test microorganisms to said foil, nutrient medium from said one compartment can permeate said foil for propagation of said microorganisms.

. 2. The process of claim 1, wherein said foil is composed of viscose.

3. As a new article of manufacture, a hermetically sealed container comprising two foils of sterilizable chemically inert plastic material sealed along their peripheries to form an airtight container, a further synthetic foil sealed along its periphery to'at least one of said first-mentioned foils subdividing said container into two compartments, a sterile nutrient medium for the propagation of microorganisms in one of said compartments, said further foil being permeable to said nutrient medium disposed within said compartment.

4. An article as defined in claim 3 wherein said further foil is composed of viscose.

References Cited in the file of this patent UNITED STATES PATENTS 2,672,431 Goetz Mar. 16, 1954 2,672,432 Goetz Mar. 16, 1954 2,677,647 Lovell May 4, 1954 

3. AS A NEW ARTICLE OF MANUFACTURE, A HERMETICALLY SEALED CONTAINER COMPRISING TWO FOILS OF STERILIZABLE CHEMICALLY INERT PLASTIC MATERIAL SEALED ALONG THEIR PERIPHERIES TO FORM AN AIRTIGHT CONTAINER, A FURTHER SYNTHETIC FOIL SEALED ALONG ITS PERIPHERY TO AT LEAST ONE OF SAID FIRST MENTIONED FOILS SUBDIVIDING SAID CONTAINER INTO TWO COMPARTMENTS, A STERILE NUTRIENT MEDIUM FOR THE PROPAGATION OFF MICROORGANIZMS IN ONE OF SAID COMPARTMENTS, SAID FURTHER FOIL BEING PERMEABLE TO SAID NUTRIENT MEDIUM DISPOSED WITHIN SAID COMPARTMENT. 